Characteristics of SEP Events and Their Solar Origin During the Evolution of Active Region NOAA 10069

Abstract

We present the results of a comparative analysis of the properties of a series of successive solar flares, which occurred in active region (AR) 10069 in August 2002, and the associated solar energetic particle (SEP) events. The active region was extremely flare productive during its evolution. The solar flare characteristics are based on X-ray and radio emission data: maximum detected photon energies and spectral index, delays between microwave, metric-radio and, hard X-ray emissions. The coronal mass ejections (CMEs) are characterized by their projected speed. The SEP properties are described by the relative electron to proton abundance as well as by the abundance of lower relative to higher energy particles. The analysis carried out supports some previous results obtained by large statistical studies, but at the same time refutes others. For example, the set of analyzed events that occurred in the AR did not show clear evidence of the big flare syndrome though the large proton events observed near Earth were always accompanied by CMEs. Some of the peculiar observations could be the result of the magnetic topology of the AR.

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Acknowledgements

This study is supported by the project ‘The origin on solar energetic particles: solar flares vs. coronal mass ejections’, co-funded by the Russian Foundation for Basic Research with project No. 17-52-18050 and the National Science Fund of Bulgaria under contract No. DNTS/Russia 01/6 (23-Jun-2017). We thank the GOES, ACE, RHESSI and RSTN teams for open access to their data. Authors are thankful to an unknown referee for the detailed reviews and the comments which helped to improve the paper. We thank the team maintaining the CME Catalog at the CDAW Data Center by NASA and the Catholic University of America in cooperation with the Naval Research Laboratory. We are thankful to the SONG team for the data. LKK thanks the budgetary funding of Basic Research program II.16.

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The authors claim that they have no conflicts of interest.

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